text: /*
   * Copyright © 2008-2010 Intel Corporation
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
   * IN THE SOFTWARE.
   *
   * Authors:
   *    Eric Anholt <eric@anholt.net>
   *    Zou Nan hai <nanhai.zou@intel.com>
   *    Xiang Hai hao<haihao.xiang@intel.com>
   *
   */
  
  #include <linux/log2.h>
  #include <drm/drmP.h>
  #include "i915_drv.h"
  #include <drm/i915_drm.h>
  #include "i915_trace.h"
  #include "intel_drv.h"
  
  /* Rough estimate of the typical request size, performing a flush,
   * set-context and then emitting the batch.
   */
  #define LEGACY_REQUEST_SIZE 200
  
  static unsigned int __intel_ring_space(unsigned int head,
  				       unsigned int tail,
  				       unsigned int size)
  {
  	/*
  	 * "If the Ring Buffer Head Pointer and the Tail Pointer are on the
  	 * same cacheline, the Head Pointer must not be greater than the Tail
  	 * Pointer."
  	 */
  	GEM_BUG_ON(!is_power_of_2(size));
  	return (head - tail - CACHELINE_BYTES) & (size - 1);
  }
  
  unsigned int intel_ring_update_space(struct intel_ring *ring)
  {
  	unsigned int space;
  
  	space = __intel_ring_space(ring->head, ring->emit, ring->size);
  
  	ring->space = space;
  	return space;
  }
  
  static int
  gen2_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
  {
  	u32 cmd, *cs;
  
  	cmd = MI_FLUSH;
  
  	if (mode & EMIT_INVALIDATE)
  		cmd |= MI_READ_FLUSH;
  
  	cs = intel_ring_begin(req, 2);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = cmd;
  	*cs++ = MI_NOOP;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static int
  gen4_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
  {
  	u32 cmd, *cs;
  
  	/*
  	 * read/write caches:
  	 *
  	 * I915_GEM_DOMAIN_RENDER is always invalidated, but is
  	 * only flushed if MI_NO_WRITE_FLUSH is unset.  On 965, it is
  	 * also flushed at 2d versus 3d pipeline switches.
  	 *
  	 * read-only caches:
  	 *
  	 * I915_GEM_DOMAIN_SAMPLER is flushed on pre-965 if
  	 * MI_READ_FLUSH is set, and is always flushed on 965.
  	 *
  	 * I915_GEM_DOMAIN_COMMAND may not exist?
  	 *
  	 * I915_GEM_DOMAIN_INSTRUCTION, which exists on 965, is
  	 * invalidated when MI_EXE_FLUSH is set.
  	 *
  	 * I915_GEM_DOMAIN_VERTEX, which exists on 965, is
  	 * invalidated with every MI_FLUSH.
  	 *
  	 * TLBs:
  	 *
  	 * On 965, TLBs associated with I915_GEM_DOMAIN_COMMAND
  	 * and I915_GEM_DOMAIN_CPU in are invalidated at PTE write and
  	 * I915_GEM_DOMAIN_RENDER and I915_GEM_DOMAIN_SAMPLER
  	 * are flushed at any MI_FLUSH.
  	 */
  
  	cmd = MI_FLUSH;
  	if (mode & EMIT_INVALIDATE) {
  		cmd |= MI_EXE_FLUSH;
  		if (IS_G4X(req->i915) || IS_GEN5(req->i915))
  			cmd |= MI_INVALIDATE_ISP;
  	}
  
  	cs = intel_ring_begin(req, 2);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = cmd;
  	*cs++ = MI_NOOP;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  /**
   * Emits a PIPE_CONTROL with a non-zero post-sync operation, for
   * implementing two workarounds on gen6.  From section 1.4.7.1
   * "PIPE_CONTROL" of the Sandy Bridge PRM volume 2 part 1:
   *
   * [DevSNB-C+{W/A}] Before any depth stall flush (including those
   * produced by non-pipelined state commands), software needs to first
   * send a PIPE_CONTROL with no bits set except Post-Sync Operation !=
   * 0.
   *
   * [Dev-SNB{W/A}]: Before a PIPE_CONTROL with Write Cache Flush Enable
   * =1, a PIPE_CONTROL with any non-zero post-sync-op is required.
   *
   * And the workaround for these two requires this workaround first:
   *
   * [Dev-SNB{W/A}]: Pipe-control with CS-stall bit set must be sent
   * BEFORE the pipe-control with a post-sync op and no write-cache
   * flushes.
   *
   * And this last workaround is tricky because of the requirements on
   * that bit.  From section 1.4.7.2.3 "Stall" of the Sandy Bridge PRM
   * volume 2 part 1:
   *
   *     "1 of the following must also be set:
   *      - Render Target Cache Flush Enable ([12] of DW1)
   *      - Depth Cache Flush Enable ([0] of DW1)
   *      - Stall at Pixel Scoreboard ([1] of DW1)
   *      - Depth Stall ([13] of DW1)
   *      - Post-Sync Operation ([13] of DW1)
   *      - Notify Enable ([8] of DW1)"
   *
   * The cache flushes require the workaround flush that triggered this
   * one, so we can't use it.  Depth stall would trigger the same.
   * Post-sync nonzero is what triggered this second workaround, so we
   * can't use that one either.  Notify enable is IRQs, which aren't
   * really our business.  That leaves only stall at scoreboard.
   */
  static int
  intel_emit_post_sync_nonzero_flush(struct drm_i915_gem_request *req)
  {
  	u32 scratch_addr =
  		i915_ggtt_offset(req->engine->scratch) + 2 * CACHELINE_BYTES;
  	u32 *cs;
  
  	cs = intel_ring_begin(req, 6);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = GFX_OP_PIPE_CONTROL(5);
  	*cs++ = PIPE_CONTROL_CS_STALL | PIPE_CONTROL_STALL_AT_SCOREBOARD;
  	*cs++ = scratch_addr | PIPE_CONTROL_GLOBAL_GTT;
  	*cs++ = 0; /* low dword */
  	*cs++ = 0; /* high dword */
  	*cs++ = MI_NOOP;
  	intel_ring_advance(req, cs);
  
  	cs = intel_ring_begin(req, 6);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = GFX_OP_PIPE_CONTROL(5);
  	*cs++ = PIPE_CONTROL_QW_WRITE;
  	*cs++ = scratch_addr | PIPE_CONTROL_GLOBAL_GTT;
  	*cs++ = 0;
  	*cs++ = 0;
  	*cs++ = MI_NOOP;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static int
  gen6_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
  {
  	u32 scratch_addr =
  		i915_ggtt_offset(req->engine->scratch) + 2 * CACHELINE_BYTES;
  	u32 *cs, flags = 0;
  	int ret;
  
  	/* Force SNB workarounds for PIPE_CONTROL flushes */
  	ret = intel_emit_post_sync_nonzero_flush(req);
  	if (ret)
  		return ret;
  
  	/* Just flush everything.  Experiments have shown that reducing the
  	 * number of bits based on the write domains has little performance
  	 * impact.
  	 */
  	if (mode & EMIT_FLUSH) {
  		flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
  		flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
  		/*
  		 * Ensure that any following seqno writes only happen
  		 * when the render cache is indeed flushed.
  		 */
  		flags |= PIPE_CONTROL_CS_STALL;
  	}
  	if (mode & EMIT_INVALIDATE) {
  		flags |= PIPE_CONTROL_TLB_INVALIDATE;
  		flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
  		/*
  		 * TLB invalidate requires a post-sync write.
  		 */
  		flags |= PIPE_CONTROL_QW_WRITE | PIPE_CONTROL_CS_STALL;
  	}
  
  	cs = intel_ring_begin(req, 4);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = GFX_OP_PIPE_CONTROL(4);
  	*cs++ = flags;
  	*cs++ = scratch_addr | PIPE_CONTROL_GLOBAL_GTT;
  	*cs++ = 0;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static int
  gen7_render_ring_cs_stall_wa(struct drm_i915_gem_request *req)
  {
  	u32 *cs;
  
  	cs = intel_ring_begin(req, 4);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = GFX_OP_PIPE_CONTROL(4);
  	*cs++ = PIPE_CONTROL_CS_STALL | PIPE_CONTROL_STALL_AT_SCOREBOARD;
  	*cs++ = 0;
  	*cs++ = 0;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static int
  gen7_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
  {
  	u32 scratch_addr =
  		i915_ggtt_offset(req->engine->scratch) + 2 * CACHELINE_BYTES;
  	u32 *cs, flags = 0;
  
  	/*
  	 * Ensure that any following seqno writes only happen when the render
  	 * cache is indeed flushed.
  	 *
  	 * Workaround: 4th PIPE_CONTROL command (except the ones with only
  	 * read-cache invalidate bits set) must have the CS_STALL bit set. We
  	 * don't try to be clever and just set it unconditionally.
  	 */
  	flags |= PIPE_CONTROL_CS_STALL;
  
  	/* Just flush everything.  Experiments have shown that reducing the
  	 * number of bits based on the write domains has little performance
  	 * impact.
  	 */
  	if (mode & EMIT_FLUSH) {
  		flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
  		flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
  		flags |= PIPE_CONTROL_DC_FLUSH_ENABLE;
  		flags |= PIPE_CONTROL_FLUSH_ENABLE;
  	}
  	if (mode & EMIT_INVALIDATE) {
  		flags |= PIPE_CONTROL_TLB_INVALIDATE;
  		flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_MEDIA_STATE_CLEAR;
  		/*
  		 * TLB invalidate requires a post-sync write.
  		 */
  		flags |= PIPE_CONTROL_QW_WRITE;
  		flags |= PIPE_CONTROL_GLOBAL_GTT_IVB;
  
  		flags |= PIPE_CONTROL_STALL_AT_SCOREBOARD;
  
  		/* Workaround: we must issue a pipe_control with CS-stall bit
  		 * set before a pipe_control command that has the state cache
  		 * invalidate bit set. */
  		gen7_render_ring_cs_stall_wa(req);
  	}
  
  	cs = intel_ring_begin(req, 4);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = GFX_OP_PIPE_CONTROL(4);
  	*cs++ = flags;
  	*cs++ = scratch_addr;
  	*cs++ = 0;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static int
  gen8_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
  {
  	u32 flags;
  	u32 *cs;
  
  	cs = intel_ring_begin(req, mode & EMIT_INVALIDATE ? 12 : 6);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	flags = PIPE_CONTROL_CS_STALL;
  
  	if (mode & EMIT_FLUSH) {
  		flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
  		flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
  		flags |= PIPE_CONTROL_DC_FLUSH_ENABLE;
  		flags |= PIPE_CONTROL_FLUSH_ENABLE;
  	}
  	if (mode & EMIT_INVALIDATE) {
  		flags |= PIPE_CONTROL_TLB_INVALIDATE;
  		flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
  		flags |= PIPE_CONTROL_QW_WRITE;
  		flags |= PIPE_CONTROL_GLOBAL_GTT_IVB;
  
  		/* WaCsStallBeforeStateCacheInvalidate:bdw,chv */
  		cs = gen8_emit_pipe_control(cs,
  					    PIPE_CONTROL_CS_STALL |
  					    PIPE_CONTROL_STALL_AT_SCOREBOARD,
  					    0);
  	}
  
  	cs = gen8_emit_pipe_control(cs, flags,
  				    i915_ggtt_offset(req->engine->scratch) +
  				    2 * CACHELINE_BYTES);
  
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static void ring_setup_phys_status_page(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  	u32 addr;
  
  	addr = dev_priv->status_page_dmah->busaddr;
  	if (INTEL_GEN(dev_priv) >= 4)
  		addr |= (dev_priv->status_page_dmah->busaddr >> 28) & 0xf0;
  	I915_WRITE(HWS_PGA, addr);
  }
  
  static void intel_ring_setup_status_page(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  	i915_reg_t mmio;
  
  	/* The ring status page addresses are no longer next to the rest of
  	 * the ring registers as of gen7.
  	 */
  	if (IS_GEN7(dev_priv)) {
  		switch (engine->id) {
  		case RCS:
  			mmio = RENDER_HWS_PGA_GEN7;
  			break;
  		case BCS:
  			mmio = BLT_HWS_PGA_GEN7;
  			break;
  		/*
  		 * VCS2 actually doesn't exist on Gen7. Only shut up
  		 * gcc switch check warning
  		 */
  		case VCS2:
  		case VCS:
  			mmio = BSD_HWS_PGA_GEN7;
  			break;
  		case VECS:
  			mmio = VEBOX_HWS_PGA_GEN7;
  			break;
  		}
  	} else if (IS_GEN6(dev_priv)) {
  		mmio = RING_HWS_PGA_GEN6(engine->mmio_base);
  	} else {
  		/* XXX: gen8 returns to sanity */
  		mmio = RING_HWS_PGA(engine->mmio_base);
  	}
  
  	I915_WRITE(mmio, engine->status_page.ggtt_offset);
  	POSTING_READ(mmio);
  
  	/*
  	 * Flush the TLB for this page
  	 *
  	 * FIXME: These two bits have disappeared on gen8, so a question
  	 * arises: do we still need this and if so how should we go about
  	 * invalidating the TLB?
  	 */
  	if (IS_GEN(dev_priv, 6, 7)) {
  		i915_reg_t reg = RING_INSTPM(engine->mmio_base);
  
  		/* ring should be idle before issuing a sync flush*/
  		WARN_ON((I915_READ_MODE(engine) & MODE_IDLE) == 0);
  
  		I915_WRITE(reg,
  			   _MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE |
  					      INSTPM_SYNC_FLUSH));
  		if (intel_wait_for_register(dev_priv,
  					    reg, INSTPM_SYNC_FLUSH, 0,
  					    1000))
  			DRM_ERROR("%s: wait for SyncFlush to complete for TLB invalidation timed out\n",
  				  engine->name);
  	}
  }
  
  static bool stop_ring(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	if (INTEL_GEN(dev_priv) > 2) {
  		I915_WRITE_MODE(engine, _MASKED_BIT_ENABLE(STOP_RING));
  		if (intel_wait_for_register(dev_priv,
  					    RING_MI_MODE(engine->mmio_base),
  					    MODE_IDLE,
  					    MODE_IDLE,
  					    1000)) {
  			DRM_ERROR("%s : timed out trying to stop ring\n",
  				  engine->name);
  			/* Sometimes we observe that the idle flag is not
  			 * set even though the ring is empty. So double
  			 * check before giving up.
  			 */
  			if (I915_READ_HEAD(engine) != I915_READ_TAIL(engine))
  				return false;
  		}
  	}
  
  	I915_WRITE_CTL(engine, 0);
  	I915_WRITE_HEAD(engine, 0);
  	I915_WRITE_TAIL(engine, 0);
  
  	if (INTEL_GEN(dev_priv) > 2) {
  		(void)I915_READ_CTL(engine);
  		I915_WRITE_MODE(engine, _MASKED_BIT_DISABLE(STOP_RING));
  	}
  
  	return (I915_READ_HEAD(engine) & HEAD_ADDR) == 0;
  }
  
  static int init_ring_common(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  	struct intel_ring *ring = engine->buffer;
  	int ret = 0;
  
  	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
  
  	if (!stop_ring(engine)) {
  		/* G45 ring initialization often fails to reset head to zero */
  		DRM_DEBUG_KMS("%s head not reset to zero "
  			      "ctl %08x head %08x tail %08x start %08x\n",
  			      engine->name,
  			      I915_READ_CTL(engine),
  			      I915_READ_HEAD(engine),
  			      I915_READ_TAIL(engine),
  			      I915_READ_START(engine));
  
  		if (!stop_ring(engine)) {
  			DRM_ERROR("failed to set %s head to zero "
  				  "ctl %08x head %08x tail %08x start %08x\n",
  				  engine->name,
  				  I915_READ_CTL(engine),
  				  I915_READ_HEAD(engine),
  				  I915_READ_TAIL(engine),
  				  I915_READ_START(engine));
  			ret = -EIO;
  			goto out;
  		}
  	}
  
  	if (HWS_NEEDS_PHYSICAL(dev_priv))
  		ring_setup_phys_status_page(engine);
  	else
  		intel_ring_setup_status_page(engine);
  
  	intel_engine_reset_breadcrumbs(engine);
  
  	/* Enforce ordering by reading HEAD register back */
  	I915_READ_HEAD(engine);
  
  	/* Initialize the ring. This must happen _after_ we've cleared the ring
  	 * registers with the above sequence (the readback of the HEAD registers
  	 * also enforces ordering), otherwise the hw might lose the new ring
  	 * register values. */
  	I915_WRITE_START(engine, i915_ggtt_offset(ring->vma));
  
  	/* WaClearRingBufHeadRegAtInit:ctg,elk */
  	if (I915_READ_HEAD(engine))
  		DRM_DEBUG("%s initialization failed [head=%08x], fudging\n",
  			  engine->name, I915_READ_HEAD(engine));
  
  	intel_ring_update_space(ring);
  	I915_WRITE_HEAD(engine, ring->head);
  	I915_WRITE_TAIL(engine, ring->tail);
  	(void)I915_READ_TAIL(engine);
  
  	I915_WRITE_CTL(engine, RING_CTL_SIZE(ring->size) | RING_VALID);
  
  	/* If the head is still not zero, the ring is dead */
  	if (intel_wait_for_register(dev_priv, RING_CTL(engine->mmio_base),
  				    RING_VALID, RING_VALID,
  				    50)) {
  		DRM_ERROR("%s initialization failed "
  			  "ctl %08x (valid? %d) head %08x [%08x] tail %08x [%08x] start %08x [expected %08x]\n",
  			  engine->name,
  			  I915_READ_CTL(engine),
  			  I915_READ_CTL(engine) & RING_VALID,
  			  I915_READ_HEAD(engine), ring->head,
  			  I915_READ_TAIL(engine), ring->tail,
  			  I915_READ_START(engine),
  			  i915_ggtt_offset(ring->vma));
  		ret = -EIO;
  		goto out;
  	}
  
  	intel_engine_init_hangcheck(engine);
  
  out:
  	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
  
  	return ret;
  }
  
  static void reset_ring_common(struct intel_engine_cs *engine,
  			      struct drm_i915_gem_request *request)
  {
  	/* Try to restore the logical GPU state to match the continuation
  	 * of the request queue. If we skip the context/PD restore, then
  	 * the next request may try to execute assuming that its context
  	 * is valid and loaded on the GPU and so may try to access invalid
  	 * memory, prompting repeated GPU hangs.
  	 *
  	 * If the request was guilty, we still restore the logical state
  	 * in case the next request requires it (e.g. the aliasing ppgtt),
  	 * but skip over the hung batch.
  	 *
  	 * If the request was innocent, we try to replay the request with
  	 * the restored context.
  	 */
  	if (request) {
  		struct drm_i915_private *dev_priv = request->i915;
  		struct intel_context *ce = &request->ctx->engine[engine->id];
  		struct i915_hw_ppgtt *ppgtt;
  
  		/* FIXME consider gen8 reset */
  
  		if (ce->state) {
  			I915_WRITE(CCID,
  				   i915_ggtt_offset(ce->state) |
  				   BIT(8) /* must be set! */ |
  				   CCID_EXTENDED_STATE_SAVE |
  				   CCID_EXTENDED_STATE_RESTORE |
  				   CCID_EN);
  		}
  
  		ppgtt = request->ctx->ppgtt ?: engine->i915->mm.aliasing_ppgtt;
  		if (ppgtt) {
  			u32 pd_offset = ppgtt->pd.base.ggtt_offset << 10;
  
  			I915_WRITE(RING_PP_DIR_DCLV(engine), PP_DIR_DCLV_2G);
  			I915_WRITE(RING_PP_DIR_BASE(engine), pd_offset);
  
  			/* Wait for the PD reload to complete */
  			if (intel_wait_for_register(dev_priv,
  						    RING_PP_DIR_BASE(engine),
  						    BIT(0), 0,
  						    10))
  				DRM_ERROR("Wait for reload of ppgtt page-directory timed out\n");
  
  			ppgtt->pd_dirty_rings &= ~intel_engine_flag(engine);
  		}
  
  		/* If the rq hung, jump to its breadcrumb and skip the batch */
  		if (request->fence.error == -EIO)
  			request->ring->head = request->postfix;
  	} else {
  		engine->legacy_active_context = NULL;
  	}
  }
  
  static int intel_rcs_ctx_init(struct drm_i915_gem_request *req)
  {
  	int ret;
  
  	ret = intel_ring_workarounds_emit(req);
  	if (ret != 0)
  		return ret;
  
  	ret = i915_gem_render_state_emit(req);
  	if (ret)
  		return ret;
  
  	return 0;
  }
  
  static int init_render_ring(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  	int ret = init_ring_common(engine);
  	if (ret)
  		return ret;
  
  	/* WaTimedSingleVertexDispatch:cl,bw,ctg,elk,ilk,snb */
  	if (IS_GEN(dev_priv, 4, 6))
  		I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(VS_TIMER_DISPATCH));
  
  	/* We need to disable the AsyncFlip performance optimisations in order
  	 * to use MI_WAIT_FOR_EVENT within the CS. It should already be
  	 * programmed to '1' on all products.
  	 *
  	 * WaDisableAsyncFlipPerfMode:snb,ivb,hsw,vlv
  	 */
  	if (IS_GEN(dev_priv, 6, 7))
  		I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(ASYNC_FLIP_PERF_DISABLE));
  
  	/* Required for the hardware to program scanline values for waiting */
  	/* WaEnableFlushTlbInvalidationMode:snb */
  	if (IS_GEN6(dev_priv))
  		I915_WRITE(GFX_MODE,
  			   _MASKED_BIT_ENABLE(GFX_TLB_INVALIDATE_EXPLICIT));
  
  	/* WaBCSVCSTlbInvalidationMode:ivb,vlv,hsw */
  	if (IS_GEN7(dev_priv))
  		I915_WRITE(GFX_MODE_GEN7,
  			   _MASKED_BIT_ENABLE(GFX_TLB_INVALIDATE_EXPLICIT) |
  			   _MASKED_BIT_ENABLE(GFX_REPLAY_MODE));
  
  	if (IS_GEN6(dev_priv)) {
  		/* From the Sandybridge PRM, volume 1 part 3, page 24:
  		 * "If this bit is set, STCunit will have LRA as replacement
  		 *  policy. [...] This bit must be reset.  LRA replacement
  		 *  policy is not supported."
  		 */
  		I915_WRITE(CACHE_MODE_0,
  			   _MASKED_BIT_DISABLE(CM0_STC_EVICT_DISABLE_LRA_SNB));
  	}
  
  	if (IS_GEN(dev_priv, 6, 7))
  		I915_WRITE(INSTPM, _MASKED_BIT_ENABLE(INSTPM_FORCE_ORDERING));
  
  	if (INTEL_INFO(dev_priv)->gen >= 6)
  		I915_WRITE_IMR(engine, ~engine->irq_keep_mask);
  
  	return init_workarounds_ring(engine);
  }
  
  static void render_ring_cleanup(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	i915_vma_unpin_and_release(&dev_priv->semaphore);
  }
  
  static u32 *gen8_rcs_signal(struct drm_i915_gem_request *req, u32 *cs)
  {
  	struct drm_i915_private *dev_priv = req->i915;
  	struct intel_engine_cs *waiter;
  	enum intel_engine_id id;
  
  	for_each_engine(waiter, dev_priv, id) {
  		u64 gtt_offset = req->engine->semaphore.signal_ggtt[id];
  		if (gtt_offset == MI_SEMAPHORE_SYNC_INVALID)
  			continue;
  
  		*cs++ = GFX_OP_PIPE_CONTROL(6);
  		*cs++ = PIPE_CONTROL_GLOBAL_GTT_IVB | PIPE_CONTROL_QW_WRITE |
  			PIPE_CONTROL_CS_STALL;
  		*cs++ = lower_32_bits(gtt_offset);
  		*cs++ = upper_32_bits(gtt_offset);
  		*cs++ = req->global_seqno;
  		*cs++ = 0;
  		*cs++ = MI_SEMAPHORE_SIGNAL |
  			MI_SEMAPHORE_TARGET(waiter->hw_id);
  		*cs++ = 0;
  	}
  
  	return cs;
  }
  
  static u32 *gen8_xcs_signal(struct drm_i915_gem_request *req, u32 *cs)
  {
  	struct drm_i915_private *dev_priv = req->i915;
  	struct intel_engine_cs *waiter;
  	enum intel_engine_id id;
  
  	for_each_engine(waiter, dev_priv, id) {
  		u64 gtt_offset = req->engine->semaphore.signal_ggtt[id];
  		if (gtt_offset == MI_SEMAPHORE_SYNC_INVALID)
  			continue;
  
  		*cs++ = (MI_FLUSH_DW + 1) | MI_FLUSH_DW_OP_STOREDW;
  		*cs++ = lower_32_bits(gtt_offset) | MI_FLUSH_DW_USE_GTT;
  		*cs++ = upper_32_bits(gtt_offset);
  		*cs++ = req->global_seqno;
  		*cs++ = MI_SEMAPHORE_SIGNAL |
  			MI_SEMAPHORE_TARGET(waiter->hw_id);
  		*cs++ = 0;
  	}
  
  	return cs;
  }
  
  static u32 *gen6_signal(struct drm_i915_gem_request *req, u32 *cs)
  {
  	struct drm_i915_private *dev_priv = req->i915;
  	struct intel_engine_cs *engine;
  	enum intel_engine_id id;
  	int num_rings = 0;
  
  	for_each_engine(engine, dev_priv, id) {
  		i915_reg_t mbox_reg;
  
  		if (!(BIT(engine->hw_id) & GEN6_SEMAPHORES_MASK))
  			continue;
  
  		mbox_reg = req->engine->semaphore.mbox.signal[engine->hw_id];
  		if (i915_mmio_reg_valid(mbox_reg)) {
  			*cs++ = MI_LOAD_REGISTER_IMM(1);
  			*cs++ = i915_mmio_reg_offset(mbox_reg);
  			*cs++ = req->global_seqno;
  			num_rings++;
  		}
  	}
  	if (num_rings & 1)
  		*cs++ = MI_NOOP;
  
  	return cs;
  }
  
  static void i9xx_submit_request(struct drm_i915_gem_request *request)
  {
  	struct drm_i915_private *dev_priv = request->i915;
  
  	i915_gem_request_submit(request);
  
  	I915_WRITE_TAIL(request->engine,
  			intel_ring_set_tail(request->ring, request->tail));
  }
  
  static void i9xx_emit_breadcrumb(struct drm_i915_gem_request *req, u32 *cs)
  {
  	*cs++ = MI_STORE_DWORD_INDEX;
  	*cs++ = I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT;
  	*cs++ = req->global_seqno;
  	*cs++ = MI_USER_INTERRUPT;
  
  	req->tail = intel_ring_offset(req, cs);
  	assert_ring_tail_valid(req->ring, req->tail);
  }
  
  static const int i9xx_emit_breadcrumb_sz = 4;
  
  /**
   * gen6_sema_emit_breadcrumb - Update the semaphore mailbox registers
   *
   * @request - request to write to the ring
   *
   * Update the mailbox registers in the *other* rings with the current seqno.
   * This acts like a signal in the canonical semaphore.
   */
  static void gen6_sema_emit_breadcrumb(struct drm_i915_gem_request *req, u32 *cs)
  {
  	return i9xx_emit_breadcrumb(req,
  				    req->engine->semaphore.signal(req, cs));
  }
  
  static void gen8_render_emit_breadcrumb(struct drm_i915_gem_request *req,
  					u32 *cs)
  {
  	struct intel_engine_cs *engine = req->engine;
  
  	if (engine->semaphore.signal)
  		cs = engine->semaphore.signal(req, cs);
  
  	*cs++ = GFX_OP_PIPE_CONTROL(6);
  	*cs++ = PIPE_CONTROL_GLOBAL_GTT_IVB | PIPE_CONTROL_CS_STALL |
  		PIPE_CONTROL_QW_WRITE;
  	*cs++ = intel_hws_seqno_address(engine);
  	*cs++ = 0;
  	*cs++ = req->global_seqno;
  	/* We're thrashing one dword of HWS. */
  	*cs++ = 0;
  	*cs++ = MI_USER_INTERRUPT;
  	*cs++ = MI_NOOP;
  
  	req->tail = intel_ring_offset(req, cs);
  	assert_ring_tail_valid(req->ring, req->tail);
  }
  
  static const int gen8_render_emit_breadcrumb_sz = 8;
  
  /**
   * intel_ring_sync - sync the waiter to the signaller on seqno
   *
   * @waiter - ring that is waiting
   * @signaller - ring which has, or will signal
   * @seqno - seqno which the waiter will block on
   */
  
  static int
  gen8_ring_sync_to(struct drm_i915_gem_request *req,
  		  struct drm_i915_gem_request *signal)
  {
  	struct drm_i915_private *dev_priv = req->i915;
  	u64 offset = GEN8_WAIT_OFFSET(req->engine, signal->engine->id);
  	struct i915_hw_ppgtt *ppgtt;
  	u32 *cs;
  
  	cs = intel_ring_begin(req, 4);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = MI_SEMAPHORE_WAIT | MI_SEMAPHORE_GLOBAL_GTT |
  		MI_SEMAPHORE_SAD_GTE_SDD;
  	*cs++ = signal->global_seqno;
  	*cs++ = lower_32_bits(offset);
  	*cs++ = upper_32_bits(offset);
  	intel_ring_advance(req, cs);
  
  	/* When the !RCS engines idle waiting upon a semaphore, they lose their
  	 * pagetables and we must reload them before executing the batch.
  	 * We do this on the i915_switch_context() following the wait and
  	 * before the dispatch.
  	 */
  	ppgtt = req->ctx->ppgtt;
  	if (ppgtt && req->engine->id != RCS)
  		ppgtt->pd_dirty_rings |= intel_engine_flag(req->engine);
  	return 0;
  }
  
  static int
  gen6_ring_sync_to(struct drm_i915_gem_request *req,
  		  struct drm_i915_gem_request *signal)
  {
  	u32 dw1 = MI_SEMAPHORE_MBOX |
  		  MI_SEMAPHORE_COMPARE |
  		  MI_SEMAPHORE_REGISTER;
  	u32 wait_mbox = signal->engine->semaphore.mbox.wait[req->engine->hw_id];
  	u32 *cs;
  
  	WARN_ON(wait_mbox == MI_SEMAPHORE_SYNC_INVALID);
  
  	cs = intel_ring_begin(req, 4);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = dw1 | wait_mbox;
  	/* Throughout all of the GEM code, seqno passed implies our current
  	 * seqno is >= the last seqno executed. However for hardware the
  	 * comparison is strictly greater than.
  	 */
  	*cs++ = signal->global_seqno - 1;
  	*cs++ = 0;
  	*cs++ = MI_NOOP;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static void
  gen5_seqno_barrier(struct intel_engine_cs *engine)
  {
  	/* MI_STORE are internally buffered by the GPU and not flushed
  	 * either by MI_FLUSH or SyncFlush or any other combination of
  	 * MI commands.
  	 *
  	 * "Only the submission of the store operation is guaranteed.
  	 * The write result will be complete (coherent) some time later
  	 * (this is practically a finite period but there is no guaranteed
  	 * latency)."
  	 *
  	 * Empirically, we observe that we need a delay of at least 75us to
  	 * be sure that the seqno write is visible by the CPU.
  	 */
  	usleep_range(125, 250);
  }
  
  static void
  gen6_seqno_barrier(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	/* Workaround to force correct ordering between irq and seqno writes on
  	 * ivb (and maybe also on snb) by reading from a CS register (like
  	 * ACTHD) before reading the status page.
  	 *
  	 * Note that this effectively stalls the read by the time it takes to
  	 * do a memory transaction, which more or less ensures that the write
  	 * from the GPU has sufficient time to invalidate the CPU cacheline.
  	 * Alternatively we could delay the interrupt from the CS ring to give
  	 * the write time to land, but that would incur a delay after every
  	 * batch i.e. much more frequent than a delay when waiting for the
  	 * interrupt (with the same net latency).
  	 *
  	 * Also note that to prevent whole machine hangs on gen7, we have to
  	 * take the spinlock to guard against concurrent cacheline access.
  	 */
  	spin_lock_irq(&dev_priv->uncore.lock);
  	POSTING_READ_FW(RING_ACTHD(engine->mmio_base));
  	spin_unlock_irq(&dev_priv->uncore.lock);
  }
  
  static void
  gen5_irq_enable(struct intel_engine_cs *engine)
  {
  	gen5_enable_gt_irq(engine->i915, engine->irq_enable_mask);
  }
  
  static void
  gen5_irq_disable(struct intel_engine_cs *engine)
  {
  	gen5_disable_gt_irq(engine->i915, engine->irq_enable_mask);
  }
  
  static void
  i9xx_irq_enable(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	dev_priv->irq_mask &= ~engine->irq_enable_mask;
  	I915_WRITE(IMR, dev_priv->irq_mask);
  	POSTING_READ_FW(RING_IMR(engine->mmio_base));
  }
  
  static void
  i9xx_irq_disable(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	dev_priv->irq_mask |= engine->irq_enable_mask;
  	I915_WRITE(IMR, dev_priv->irq_mask);
  }
  
  static void
  i8xx_irq_enable(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	dev_priv->irq_mask &= ~engine->irq_enable_mask;
  	I915_WRITE16(IMR, dev_priv->irq_mask);
  	POSTING_READ16(RING_IMR(engine->mmio_base));
  }
  
  static void
  i8xx_irq_disable(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	dev_priv->irq_mask |= engine->irq_enable_mask;
  	I915_WRITE16(IMR, dev_priv->irq_mask);
  }
  
  static int
  bsd_ring_flush(struct drm_i915_gem_request *req, u32 mode)
  {
  	u32 *cs;
  
  	cs = intel_ring_begin(req, 2);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = MI_FLUSH;
  	*cs++ = MI_NOOP;
  	intel_ring_advance(req, cs);
  	return 0;
  }
  
  static void
  gen6_irq_enable(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	I915_WRITE_IMR(engine,
  		       ~(engine->irq_enable_mask |
  			 engine->irq_keep_mask));
  	gen5_enable_gt_irq(dev_priv, engine->irq_enable_mask);
  }
  
  static void
  gen6_irq_disable(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	I915_WRITE_IMR(engine, ~engine->irq_keep_mask);
  	gen5_disable_gt_irq(dev_priv, engine->irq_enable_mask);
  }
  
  static void
  hsw_vebox_irq_enable(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	I915_WRITE_IMR(engine, ~engine->irq_enable_mask);
  	gen6_unmask_pm_irq(dev_priv, engine->irq_enable_mask);
  }
  
  static void
  hsw_vebox_irq_disable(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	I915_WRITE_IMR(engine, ~0);
  	gen6_mask_pm_irq(dev_priv, engine->irq_enable_mask);
  }
  
  static void
  gen8_irq_enable(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	I915_WRITE_IMR(engine,
  		       ~(engine->irq_enable_mask |
  			 engine->irq_keep_mask));
  	POSTING_READ_FW(RING_IMR(engine->mmio_base));
  }
  
  static void
  gen8_irq_disable(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	I915_WRITE_IMR(engine, ~engine->irq_keep_mask);
  }
  
  static int
  i965_emit_bb_start(struct drm_i915_gem_request *req,
  		   u64 offset, u32 length,
  		   unsigned int dispatch_flags)
  {
  	u32 *cs;
  
  	cs = intel_ring_begin(req, 2);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = MI_BATCH_BUFFER_START | MI_BATCH_GTT | (dispatch_flags &
  		I915_DISPATCH_SECURE ? 0 : MI_BATCH_NON_SECURE_I965);
  	*cs++ = offset;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  /* Just userspace ABI convention to limit the wa batch bo to a resonable size */
  #define I830_BATCH_LIMIT (256*1024)
  #define I830_TLB_ENTRIES (2)
  #define I830_WA_SIZE max(I830_TLB_ENTRIES*4096, I830_BATCH_LIMIT)
  static int
  i830_emit_bb_start(struct drm_i915_gem_request *req,
  		   u64 offset, u32 len,
  		   unsigned int dispatch_flags)
  {
  	u32 *cs, cs_offset = i915_ggtt_offset(req->engine->scratch);
  
  	cs = intel_ring_begin(req, 6);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	/* Evict the invalid PTE TLBs */
  	*cs++ = COLOR_BLT_CMD | BLT_WRITE_RGBA;
  	*cs++ = BLT_DEPTH_32 | BLT_ROP_COLOR_COPY | 4096;
  	*cs++ = I830_TLB_ENTRIES << 16 | 4; /* load each page */
  	*cs++ = cs_offset;
  	*cs++ = 0xdeadbeef;
  	*cs++ = MI_NOOP;
  	intel_ring_advance(req, cs);
  
  	if ((dispatch_flags & I915_DISPATCH_PINNED) == 0) {
  		if (len > I830_BATCH_LIMIT)
  			return -ENOSPC;
  
  		cs = intel_ring_begin(req, 6 + 2);
  		if (IS_ERR(cs))
  			return PTR_ERR(cs);
  
  		/* Blit the batch (which has now all relocs applied) to the
  		 * stable batch scratch bo area (so that the CS never
  		 * stumbles over its tlb invalidation bug) ...
  		 */
  		*cs++ = SRC_COPY_BLT_CMD | BLT_WRITE_RGBA;
  		*cs++ = BLT_DEPTH_32 | BLT_ROP_SRC_COPY | 4096;
  		*cs++ = DIV_ROUND_UP(len, 4096) << 16 | 4096;
  		*cs++ = cs_offset;
  		*cs++ = 4096;
  		*cs++ = offset;
  
  		*cs++ = MI_FLUSH;
  		*cs++ = MI_NOOP;
  		intel_ring_advance(req, cs);
  
  		/* ... and execute it. */
  		offset = cs_offset;
  	}
  
  	cs = intel_ring_begin(req, 2);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = MI_BATCH_BUFFER_START | MI_BATCH_GTT;
  	*cs++ = offset | (dispatch_flags & I915_DISPATCH_SECURE ? 0 :
  		MI_BATCH_NON_SECURE);
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static int
  i915_emit_bb_start(struct drm_i915_gem_request *req,
  		   u64 offset, u32 len,
  		   unsigned int dispatch_flags)
  {
  	u32 *cs;
  
  	cs = intel_ring_begin(req, 2);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = MI_BATCH_BUFFER_START | MI_BATCH_GTT;
  	*cs++ = offset | (dispatch_flags & I915_DISPATCH_SECURE ? 0 :
  		MI_BATCH_NON_SECURE);
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static void cleanup_phys_status_page(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	if (!dev_priv->status_page_dmah)
  		return;
  
  	drm_pci_free(&dev_priv->drm, dev_priv->status_page_dmah);
  	engine->status_page.page_addr = NULL;
  }
  
  static void cleanup_status_page(struct intel_engine_cs *engine)
  {
  	struct i915_vma *vma;
  	struct drm_i915_gem_object *obj;
  
  	vma = fetch_and_zero(&engine->status_page.vma);
  	if (!vma)
  		return;
  
  	obj = vma->obj;
  
  	i915_vma_unpin(vma);
  	i915_vma_close(vma);
  
  	i915_gem_object_unpin_map(obj);
  	__i915_gem_object_release_unless_active(obj);
  }
  
  static int init_status_page(struct intel_engine_cs *engine)
  {
  	struct drm_i915_gem_object *obj;
  	struct i915_vma *vma;
  	unsigned int flags;
  	void *vaddr;
  	int ret;
  
  	obj = i915_gem_object_create_internal(engine->i915, PAGE_SIZE);
  	if (IS_ERR(obj)) {
  		DRM_ERROR("Failed to allocate status page\n");
  		return PTR_ERR(obj);
  	}
  
  	ret = i915_gem_object_set_cache_level(obj, I915_CACHE_LLC);
  	if (ret)
  		goto err;
  
  	vma = i915_vma_instance(obj, &engine->i915->ggtt.base, NULL);
  	if (IS_ERR(vma)) {
  		ret = PTR_ERR(vma);
  		goto err;
  	}
  
  	flags = PIN_GLOBAL;
  	if (!HAS_LLC(engine->i915))
  		/* On g33, we cannot place HWS above 256MiB, so
  		 * restrict its pinning to the low mappable arena.
  		 * Though this restriction is not documented for
  		 * gen4, gen5, or byt, they also behave similarly
  		 * and hang if the HWS is placed at the top of the
  		 * GTT. To generalise, it appears that all !llc
  		 * platforms have issues with us placing the HWS
  		 * above the mappable region (even though we never
  		 * actualy map it).
  		 */
  		flags |= PIN_MAPPABLE;
  	ret = i915_vma_pin(vma, 0, 4096, flags);
  	if (ret)
  		goto err;
  
  	vaddr = i915_gem_object_pin_map(obj, I915_MAP_WB);
  	if (IS_ERR(vaddr)) {
  		ret = PTR_ERR(vaddr);
  		goto err_unpin;
  	}
  
  	engine->status_page.vma = vma;
  	engine->status_page.ggtt_offset = i915_ggtt_offset(vma);
  	engine->status_page.page_addr = memset(vaddr, 0, PAGE_SIZE);
  
  	DRM_DEBUG_DRIVER("%s hws offset: 0x%08x\n",
  			 engine->name, i915_ggtt_offset(vma));
  	return 0;
  
  err_unpin:
  	i915_vma_unpin(vma);
  err:
  	i915_gem_object_put(obj);
  	return ret;
  }
  
  static int init_phys_status_page(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	GEM_BUG_ON(engine->id != RCS);
  
  	dev_priv->status_page_dmah =
  		drm_pci_alloc(&dev_priv->drm, PAGE_SIZE, PAGE_SIZE);
  	if (!dev_priv->status_page_dmah)
  		return -ENOMEM;
  
  	engine->status_page.page_addr = dev_priv->status_page_dmah->vaddr;
  	memset(engine->status_page.page_addr, 0, PAGE_SIZE);
  
  	return 0;
  }
  
  int intel_ring_pin(struct intel_ring *ring,
  		   struct drm_i915_private *i915,
  		   unsigned int offset_bias)
  {
  	enum i915_map_type map = HAS_LLC(i915) ? I915_MAP_WB : I915_MAP_WC;
  	struct i915_vma *vma = ring->vma;
  	unsigned int flags;
  	void *addr;
  	int ret;
  
  	GEM_BUG_ON(ring->vaddr);
  
  
  	flags = PIN_GLOBAL;
  	if (offset_bias)
  		flags |= PIN_OFFSET_BIAS | offset_bias;
  	if (vma->obj->stolen)
  		flags |= PIN_MAPPABLE;
  
  	if (!(vma->flags & I915_VMA_GLOBAL_BIND)) {
  		if (flags & PIN_MAPPABLE || map == I915_MAP_WC)
  			ret = i915_gem_object_set_to_gtt_domain(vma->obj, true);
  		else
  			ret = i915_gem_object_set_to_cpu_domain(vma->obj, true);
  		if (unlikely(ret))
  			return ret;
  	}
  
  	ret = i915_vma_pin(vma, 0, PAGE_SIZE, flags);
  	if (unlikely(ret))
  		return ret;
  
  	if (i915_vma_is_map_and_fenceable(vma))
  		addr = (void __force *)i915_vma_pin_iomap(vma);
  	else
  		addr = i915_gem_object_pin_map(vma->obj, map);
  	if (IS_ERR(addr))
  		goto err;
  
  	ring->vaddr = addr;
  	return 0;
  
  err:
  	i915_vma_unpin(vma);
  	return PTR_ERR(addr);
  }
  
  void intel_ring_reset(struct intel_ring *ring, u32 tail)
  {
  	GEM_BUG_ON(!list_empty(&ring->request_list));
  	ring->tail = tail;
  	ring->head = tail;
  	ring->emit = tail;
  	intel_ring_update_space(ring);
  }
  
  void intel_ring_unpin(struct intel_ring *ring)
  {
  	GEM_BUG_ON(!ring->vma);
  	GEM_BUG_ON(!ring->vaddr);
  
  	/* Discard any unused bytes beyond that submitted to hw. */
  	intel_ring_reset(ring, ring->tail);
  
  	if (i915_vma_is_map_and_fenceable(ring->vma))
  		i915_vma_unpin_iomap(ring->vma);
  	else
  		i915_gem_object_unpin_map(ring->vma->obj);
  	ring->vaddr = NULL;
  
  	i915_vma_unpin(ring->vma);
  }
  
  static struct i915_vma *
  intel_ring_create_vma(struct drm_i915_private *dev_priv, int size)
  {
  	struct drm_i915_gem_object *obj;
  	struct i915_vma *vma;
  
  	obj = i915_gem_object_create_stolen(dev_priv, size);
  	if (!obj)
  		obj = i915_gem_object_create_internal(dev_priv, size);
  	if (IS_ERR(obj))
  		return ERR_CAST(obj);
  
  	/* mark ring buffers as read-only from GPU side by default */
  	obj->gt_ro = 1;
  
  	vma = i915_vma_instance(obj, &dev_priv->ggtt.base, NULL);
  	if (IS_ERR(vma))
  		goto err;
  
  	return vma;
  
  err:
  	i915_gem_object_put(obj);
  	return vma;
  }
  
  struct intel_ring *
  intel_engine_create_ring(struct intel_engine_cs *engine, int size)
  {
  	struct intel_ring *ring;
  	struct i915_vma *vma;
  
  	GEM_BUG_ON(!is_power_of_2(size));
  	GEM_BUG_ON(RING_CTL_SIZE(size) & ~RING_NR_PAGES);
  
  	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
  	if (!ring)
  		return ERR_PTR(-ENOMEM);
  
  	INIT_LIST_HEAD(&ring->request_list);
  
  	ring->size = size;
  	/* Workaround an erratum on the i830 which causes a hang if
  	 * the TAIL pointer points to within the last 2 cachelines
  	 * of the buffer.
  	 */
  	ring->effective_size = size;
  	if (IS_I830(engine->i915) || IS_I845G(engine->i915))
  		ring->effective_size -= 2 * CACHELINE_BYTES;
  
  	intel_ring_update_space(ring);
  
  	vma = intel_ring_create_vma(engine->i915, size);
  	if (IS_ERR(vma)) {
  		kfree(ring);
  		return ERR_CAST(vma);
  	}
  	ring->vma = vma;
  
  	return ring;
  }
  
  void
  intel_ring_free(struct intel_ring *ring)
  {
  	struct drm_i915_gem_object *obj = ring->vma->obj;
  
  	i915_vma_close(ring->vma);
  	__i915_gem_object_release_unless_active(obj);
  
  	kfree(ring);
  }
  
  static int context_pin(struct i915_gem_context *ctx)
  {
  	struct i915_vma *vma = ctx->engine[RCS].state;
  	int ret;
  
  	/* Clear this page out of any CPU caches for coherent swap-in/out.
  	 * We only want to do this on the first bind so that we do not stall
  	 * on an active context (which by nature is already on the GPU).
  	 */
  	if (!(vma->flags & I915_VMA_GLOBAL_BIND)) {
  		ret = i915_gem_object_set_to_gtt_domain(vma->obj, false);
  		if (ret)
  			return ret;
  	}
  
  	return i915_vma_pin(vma, 0, I915_GTT_MIN_ALIGNMENT,
  			    PIN_GLOBAL | PIN_HIGH);
  }
  
  static struct i915_vma *
  alloc_context_vma(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *i915 = engine->i915;
  	struct drm_i915_gem_object *obj;
  	struct i915_vma *vma;
  
  	obj = i915_gem_object_create(i915, engine->context_size);
  	if (IS_ERR(obj))
  		return ERR_CAST(obj);
  
  	/*
  	 * Try to make the context utilize L3 as well as LLC.
  	 *
  	 * On VLV we don't have L3 controls in the PTEs so we
  	 * shouldn't touch the cache level, especially as that
  	 * would make the object snooped which might have a
  	 * negative performance impact.
  	 *
  	 * Snooping is required on non-llc platforms in execlist
  	 * mode, but since all GGTT accesses use PAT entry 0 we
  	 * get snooping anyway regardless of cache_level.
  	 *
  	 * This is only applicable for Ivy Bridge devices since
  	 * later platforms don't have L3 control bits in the PTE.
  	 */
  	if (IS_IVYBRIDGE(i915)) {
  		/* Ignore any error, regard it as a simple optimisation */
  		i915_gem_object_set_cache_level(obj, I915_CACHE_L3_LLC);
  	}
  
  	vma = i915_vma_instance(obj, &i915->ggtt.base, NULL);
  	if (IS_ERR(vma))
  		i915_gem_object_put(obj);
  
  	return vma;
  }
  
  static struct intel_ring *
  intel_ring_context_pin(struct intel_engine_cs *engine,
  		       struct i915_gem_context *ctx)
  {
  	struct intel_context *ce = &ctx->engine[engine->id];
  	int ret;
  
  	lockdep_assert_held(&ctx->i915->drm.struct_mutex);
  
  	if (likely(ce->pin_count++))
  		goto out;
  	GEM_BUG_ON(!ce->pin_count); /* no overflow please! */
  
  	if (!ce->state && engine->context_size) {
  		struct i915_vma *vma;
  
  		vma = alloc_context_vma(engine);
  		if (IS_ERR(vma)) {
  			ret = PTR_ERR(vma);
  			goto err;
  		}
  
  		ce->state = vma;
  	}
  
  	if (ce->state) {
  		ret = context_pin(ctx);
  		if (ret)
  			goto err;
  
  		ce->state->obj->mm.dirty = true;
  	}
  
  	/* The kernel context is only used as a placeholder for flushing the
  	 * active context. It is never used for submitting user rendering and
  	 * as such never requires the golden render context, and so we can skip
  	 * emitting it when we switch to the kernel context. This is required
  	 * as during eviction we cannot allocate and pin the renderstate in
  	 * order to initialise the context.
  	 */
  	if (i915_gem_context_is_kernel(ctx))
  		ce->initialised = true;
  
  	i915_gem_context_get(ctx);
  
  out:
  	/* One ringbuffer to rule them all */
  	return engine->buffer;
  
  err:
  	ce->pin_count = 0;
  	return ERR_PTR(ret);
  }
  
  static void intel_ring_context_unpin(struct intel_engine_cs *engine,
  				     struct i915_gem_context *ctx)
  {
  	struct intel_context *ce = &ctx->engine[engine->id];
  
  	lockdep_assert_held(&ctx->i915->drm.struct_mutex);
  	GEM_BUG_ON(ce->pin_count == 0);
  
  	if (--ce->pin_count)
  		return;
  
  	if (ce->state)
  		i915_vma_unpin(ce->state);
  
  	i915_gem_context_put(ctx);
  }
  
  static int intel_init_ring_buffer(struct intel_engine_cs *engine)
  {
  	struct intel_ring *ring;
  	int err;
  
  	intel_engine_setup_common(engine);
  
  	err = intel_engine_init_common(engine);
  	if (err)
  		goto err;
  
  	if (HWS_NEEDS_PHYSICAL(engine->i915))
  		err = init_phys_status_page(engine);
  	else
  		err = init_status_page(engine);
  	if (err)
  		goto err;
  
  	ring = intel_engine_create_ring(engine, 32 * PAGE_SIZE);
  	if (IS_ERR(ring)) {
  		err = PTR_ERR(ring);
  		goto err_hws;
  	}
  
  	/* Ring wraparound at offset 0 sometimes hangs. No idea why. */
  	err = intel_ring_pin(ring, engine->i915, I915_GTT_PAGE_SIZE);
  	if (err)
  		goto err_ring;
  
  	GEM_BUG_ON(engine->buffer);
  	engine->buffer = ring;
  
  	return 0;
  
  err_ring:
  	intel_ring_free(ring);
  err_hws:
  	if (HWS_NEEDS_PHYSICAL(engine->i915))
  		cleanup_phys_status_page(engine);
  	else
  		cleanup_status_page(engine);
  err:
  	intel_engine_cleanup_common(engine);
  	return err;
  }
  
  void intel_engine_cleanup(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	WARN_ON(INTEL_GEN(dev_priv) > 2 &&
  		(I915_READ_MODE(engine) & MODE_IDLE) == 0);
  
  	intel_ring_unpin(engine->buffer);
  	intel_ring_free(engine->buffer);
  
  	if (engine->cleanup)
  		engine->cleanup(engine);
  
  	if (HWS_NEEDS_PHYSICAL(dev_priv))
  		cleanup_phys_status_page(engine);
  	else
  		cleanup_status_page(engine);
  
  	intel_engine_cleanup_common(engine);
  
  	dev_priv->engine[engine->id] = NULL;
  	kfree(engine);
  }
  
  void intel_legacy_submission_resume(struct drm_i915_private *dev_priv)
  {
  	struct intel_engine_cs *engine;
  	enum intel_engine_id id;
  
  	/* Restart from the beginning of the rings for convenience */
  	for_each_engine(engine, dev_priv, id)
  		intel_ring_reset(engine->buffer, 0);
  }
  
  static int ring_request_alloc(struct drm_i915_gem_request *request)
  {
  	u32 *cs;
  
  	GEM_BUG_ON(!request->ctx->engine[request->engine->id].pin_count);
  
  	/* Flush enough space to reduce the likelihood of waiting after
  	 * we start building the request - in which case we will just
  	 * have to repeat work.
  	 */
  	request->reserved_space += LEGACY_REQUEST_SIZE;
  
  	cs = intel_ring_begin(request, 0);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	request->reserved_space -= LEGACY_REQUEST_SIZE;
  	return 0;
  }
  
  static noinline int wait_for_space(struct drm_i915_gem_request *req,
  				   unsigned int bytes)
  {
  	struct intel_ring *ring = req->ring;
  	struct drm_i915_gem_request *target;
  	long timeout;
  
  	lockdep_assert_held(&req->i915->drm.struct_mutex);
  
  	if (intel_ring_update_space(ring) >= bytes)
  		return 0;
  
  	/*
  	 * Space is reserved in the ringbuffer for finalising the request,
  	 * as that cannot be allowed to fail. During request finalisation,
  	 * reserved_space is set to 0 to stop the overallocation and the
  	 * assumption is that then we never need to wait (which has the
  	 * risk of failing with EINTR).
  	 *
  	 * See also i915_gem_request_alloc() and i915_add_request().
  	 */
  	GEM_BUG_ON(!req->reserved_space);
  
  	list_for_each_entry(target, &ring->request_list, ring_link) {
  		/* Would completion of this request free enough space? */
  		if (bytes <= __intel_ring_space(target->postfix,
  						ring->emit, ring->size))
  			break;
  	}
  
  	if (WARN_ON(&target->ring_link == &ring->request_list))
  		return -ENOSPC;
  
  	timeout = i915_wait_request(target,
  				    I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
  				    MAX_SCHEDULE_TIMEOUT);
  	if (timeout < 0)
  		return timeout;
  
  	i915_gem_request_retire_upto(target);
  
  	intel_ring_update_space(ring);
  	GEM_BUG_ON(ring->space < bytes);
  	return 0;
  }
  
  u32 *intel_ring_begin(struct drm_i915_gem_request *req,
  		      unsigned int num_dwords)
  {
  	struct intel_ring *ring = req->ring;
  	const unsigned int remain_usable = ring->effective_size - ring->emit;
  	const unsigned int bytes = num_dwords * sizeof(u32);
  	unsigned int need_wrap = 0;
  	unsigned int total_bytes;
  	u32 *cs;
  
  	/* Packets must be qword aligned. */
  	GEM_BUG_ON(num_dwords & 1);
  
  	total_bytes = bytes + req->reserved_space;
  	GEM_BUG_ON(total_bytes > ring->effective_size);
  
  	if (unlikely(total_bytes > remain_usable)) {
  		const int remain_actual = ring->size - ring->emit;
  
  		if (bytes > remain_usable) {
  			/*
  			 * Not enough space for the basic request. So need to
  			 * flush out the remainder and then wait for
  			 * base + reserved.
  			 */
  			total_bytes += remain_actual;
  			need_wrap = remain_actual | 1;
  		} else  {
  			/*
  			 * The base request will fit but the reserved space
  			 * falls off the end. So we don't need an immediate
  			 * wrap and only need to effectively wait for the
  			 * reserved size from the start of ringbuffer.
  			 */
  			total_bytes = req->reserved_space + remain_actual;
  		}
  	}
  
  	if (unlikely(total_bytes > ring->space)) {
  		int ret = wait_for_space(req, total_bytes);
  		if (unlikely(ret))
  			return ERR_PTR(ret);
  	}
  
  	if (unlikely(need_wrap)) {
  		need_wrap &= ~1;
  		GEM_BUG_ON(need_wrap > ring->space);
  		GEM_BUG_ON(ring->emit + need_wrap > ring->size);
  
  		/* Fill the tail with MI_NOOP */
  		memset(ring->vaddr + ring->emit, 0, need_wrap);
  		ring->emit = 0;
  		ring->space -= need_wrap;
  	}
  
  	GEM_BUG_ON(ring->emit > ring->size - bytes);
  	GEM_BUG_ON(ring->space < bytes);
  	cs = ring->vaddr + ring->emit;
  	GEM_DEBUG_EXEC(memset(cs, POISON_INUSE, bytes));
  	ring->emit += bytes;
  	ring->space -= bytes;
  
  	return cs;
  }
  
  /* Align the ring tail to a cacheline boundary */
  int intel_ring_cacheline_align(struct drm_i915_gem_request *req)
  {
  	int num_dwords =
  		(req->ring->emit & (CACHELINE_BYTES - 1)) / sizeof(uint32_t);
  	u32 *cs;
  
  	if (num_dwords == 0)
  		return 0;
  
  	num_dwords = CACHELINE_BYTES / sizeof(uint32_t) - num_dwords;
  	cs = intel_ring_begin(req, num_dwords);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	while (num_dwords--)
  		*cs++ = MI_NOOP;
  
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static void gen6_bsd_submit_request(struct drm_i915_gem_request *request)
  {
  	struct drm_i915_private *dev_priv = request->i915;
  
  	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
  
         /* Every tail move must follow the sequence below */
  
  	/* Disable notification that the ring is IDLE. The GT
  	 * will then assume that it is busy and bring it out of rc6.
  	 */
  	I915_WRITE_FW(GEN6_BSD_SLEEP_PSMI_CONTROL,
  		      _MASKED_BIT_ENABLE(GEN6_BSD_SLEEP_MSG_DISABLE));
  
  	/* Clear the context id. Here be magic! */
  	I915_WRITE64_FW(GEN6_BSD_RNCID, 0x0);
  
  	/* Wait for the ring not to be idle, i.e. for it to wake up. */
  	if (__intel_wait_for_register_fw(dev_priv,
  					 GEN6_BSD_SLEEP_PSMI_CONTROL,
  					 GEN6_BSD_SLEEP_INDICATOR,
  					 0,
  					 1000, 0, NULL))
  		DRM_ERROR("timed out waiting for the BSD ring to wake up\n");
  
  	/* Now that the ring is fully powered up, update the tail */
  	i9xx_submit_request(request);
  
  	/* Let the ring send IDLE messages to the GT again,
  	 * and so let it sleep to conserve power when idle.
  	 */
  	I915_WRITE_FW(GEN6_BSD_SLEEP_PSMI_CONTROL,
  		      _MASKED_BIT_DISABLE(GEN6_BSD_SLEEP_MSG_DISABLE));
  
  	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
  }
  
  static int gen6_bsd_ring_flush(struct drm_i915_gem_request *req, u32 mode)
  {
  	u32 cmd, *cs;
  
  	cs = intel_ring_begin(req, 4);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	cmd = MI_FLUSH_DW;
  	if (INTEL_GEN(req->i915) >= 8)
  		cmd += 1;
  
  	/* We always require a command barrier so that subsequent
  	 * commands, such as breadcrumb interrupts, are strictly ordered
  	 * wrt the contents of the write cache being flushed to memory
  	 * (and thus being coherent from the CPU).
  	 */
  	cmd |= MI_FLUSH_DW_STORE_INDEX | MI_FLUSH_DW_OP_STOREDW;
  
  	/*
  	 * Bspec vol 1c.5 - video engine command streamer:
  	 * "If ENABLED, all TLBs will be invalidated once the flush
  	 * operation is complete. This bit is only valid when the
  	 * Post-Sync Operation field is a value of 1h or 3h."
  	 */
  	if (mode & EMIT_INVALIDATE)
  		cmd |= MI_INVALIDATE_TLB | MI_INVALIDATE_BSD;
  
  	*cs++ = cmd;
  	*cs++ = I915_GEM_HWS_SCRATCH_ADDR | MI_FLUSH_DW_USE_GTT;
  	if (INTEL_GEN(req->i915) >= 8) {
  		*cs++ = 0; /* upper addr */
  		*cs++ = 0; /* value */
  	} else  {
  		*cs++ = 0;
  		*cs++ = MI_NOOP;
  	}
  	intel_ring_advance(req, cs);
  	return 0;
  }
  
  static int
  gen8_emit_bb_start(struct drm_i915_gem_request *req,
  		   u64 offset, u32 len,
  		   unsigned int dispatch_flags)
  {
  	bool ppgtt = USES_PPGTT(req->i915) &&
  			!(dispatch_flags & I915_DISPATCH_SECURE);
  	u32 *cs;
  
  	cs = intel_ring_begin(req, 4);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	/* FIXME(BDW): Address space and security selectors. */
  	*cs++ = MI_BATCH_BUFFER_START_GEN8 | (ppgtt << 8) | (dispatch_flags &
  		I915_DISPATCH_RS ? MI_BATCH_RESOURCE_STREAMER : 0);
  	*cs++ = lower_32_bits(offset);
  	*cs++ = upper_32_bits(offset);
  	*cs++ = MI_NOOP;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static int
  hsw_emit_bb_start(struct drm_i915_gem_request *req,
  		  u64 offset, u32 len,
  		  unsigned int dispatch_flags)
  {
  	u32 *cs;
  
  	cs = intel_ring_begin(req, 2);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = MI_BATCH_BUFFER_START | (dispatch_flags & I915_DISPATCH_SECURE ?
  		0 : MI_BATCH_PPGTT_HSW | MI_BATCH_NON_SECURE_HSW) |
  		(dispatch_flags & I915_DISPATCH_RS ?
  		MI_BATCH_RESOURCE_STREAMER : 0);
  	/* bit0-7 is the length on GEN6+ */
  	*cs++ = offset;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static int
  gen6_emit_bb_start(struct drm_i915_gem_request *req,
  		   u64 offset, u32 len,
  		   unsigned int dispatch_flags)
  {
  	u32 *cs;
  
  	cs = intel_ring_begin(req, 2);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	*cs++ = MI_BATCH_BUFFER_START | (dispatch_flags & I915_DISPATCH_SECURE ?
  		0 : MI_BATCH_NON_SECURE_I965);
  	/* bit0-7 is the length on GEN6+ */
  	*cs++ = offset;
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  /* Blitter support (SandyBridge+) */
  
  static int gen6_ring_flush(struct drm_i915_gem_request *req, u32 mode)
  {
  	u32 cmd, *cs;
  
  	cs = intel_ring_begin(req, 4);
  	if (IS_ERR(cs))
  		return PTR_ERR(cs);
  
  	cmd = MI_FLUSH_DW;
  	if (INTEL_GEN(req->i915) >= 8)
  		cmd += 1;
  
  	/* We always require a command barrier so that subsequent
  	 * commands, such as breadcrumb interrupts, are strictly ordered
  	 * wrt the contents of the write cache being flushed to memory
  	 * (and thus being coherent from the CPU).
  	 */
  	cmd |= MI_FLUSH_DW_STORE_INDEX | MI_FLUSH_DW_OP_STOREDW;
  
  	/*
  	 * Bspec vol 1c.3 - blitter engine command streamer:
  	 * "If ENABLED, all TLBs will be invalidated once the flush
  	 * operation is complete. This bit is only valid when the
  	 * Post-Sync Operation field is a value of 1h or 3h."
  	 */
  	if (mode & EMIT_INVALIDATE)
  		cmd |= MI_INVALIDATE_TLB;
  	*cs++ = cmd;
  	*cs++ = I915_GEM_HWS_SCRATCH_ADDR | MI_FLUSH_DW_USE_GTT;
  	if (INTEL_GEN(req->i915) >= 8) {
  		*cs++ = 0; /* upper addr */
  		*cs++ = 0; /* value */
  	} else  {
  		*cs++ = 0;
  		*cs++ = MI_NOOP;
  	}
  	intel_ring_advance(req, cs);
  
  	return 0;
  }
  
  static void intel_ring_init_semaphores(struct drm_i915_private *dev_priv,
  				       struct intel_engine_cs *engine)
  {
  	struct drm_i915_gem_object *obj;
  	int ret, i;
  
  	if (!i915.semaphores)
  		return;
  
  	if (INTEL_GEN(dev_priv) >= 8 && !dev_priv->semaphore) {
  		struct i915_vma *vma;
  
  		obj = i915_gem_object_create(dev_priv, PAGE_SIZE);
  		if (IS_ERR(obj))
  			goto err;
  
  		vma = i915_vma_instance(obj, &dev_priv->ggtt.base, NULL);
  		if (IS_ERR(vma))
  			goto err_obj;
  
  		ret = i915_gem_object_set_to_gtt_domain(obj, false);
  		if (ret)
  			goto err_obj;
  
  		ret = i915_vma_pin(vma, 0, 0, PIN_GLOBAL | PIN_HIGH);
  		if (ret)
  			goto err_obj;
  
  		dev_priv->semaphore = vma;
  	}
  
  	if (INTEL_GEN(dev_priv) >= 8) {
  		u32 offset = i915_ggtt_offset(dev_priv->semaphore);
  
  		engine->semaphore.sync_to = gen8_ring_sync_to;
  		engine->semaphore.signal = gen8_xcs_signal;
  
  		for (i = 0; i < I915_NUM_ENGINES; i++) {
  			u32 ring_offset;
  
  			if (i != engine->id)
  				ring_offset = offset + GEN8_SEMAPHORE_OFFSET(engine->id, i);
  			else
  				ring_offset = MI_SEMAPHORE_SYNC_INVALID;
  
  			engine->semaphore.signal_ggtt[i] = ring_offset;
  		}
  	} else if (INTEL_GEN(dev_priv) >= 6) {
  		engine->semaphore.sync_to = gen6_ring_sync_to;
  		engine->semaphore.signal = gen6_signal;
  
  		/*
  		 * The current semaphore is only applied on pre-gen8
  		 * platform.  And there is no VCS2 ring on the pre-gen8
  		 * platform. So the semaphore between RCS and VCS2 is
  		 * initialized as INVALID.  Gen8 will initialize the
  		 * sema between VCS2 and RCS later.
  		 */
  		for (i = 0; i < GEN6_NUM_SEMAPHORES; i++) {
  			static const struct {
  				u32 wait_mbox;
  				i915_reg_t mbox_reg;
  			} sem_data[GEN6_NUM_SEMAPHORES][GEN6_NUM_SEMAPHORES] = {
  				[RCS_HW] = {
  					[VCS_HW] =  { .wait_mbox = MI_SEMAPHORE_SYNC_RV,  .mbox_reg = GEN6_VRSYNC },
  					[BCS_HW] =  { .wait_mbox = MI_SEMAPHORE_SYNC_RB,  .mbox_reg = GEN6_BRSYNC },
  					[VECS_HW] = { .wait_mbox = MI_SEMAPHORE_SYNC_RVE, .mbox_reg = GEN6_VERSYNC },
  				},
  				[VCS_HW] = {
  					[RCS_HW] =  { .wait_mbox = MI_SEMAPHORE_SYNC_VR,  .mbox_reg = GEN6_RVSYNC },
  					[BCS_HW] =  { .wait_mbox = MI_SEMAPHORE_SYNC_VB,  .mbox_reg = GEN6_BVSYNC },
  					[VECS_HW] = { .wait_mbox = MI_SEMAPHORE_SYNC_VVE, .mbox_reg = GEN6_VEVSYNC },
  				},
  				[BCS_HW] = {
  					[RCS_HW] =  { .wait_mbox = MI_SEMAPHORE_SYNC_BR,  .mbox_reg = GEN6_RBSYNC },
  					[VCS_HW] =  { .wait_mbox = MI_SEMAPHORE_SYNC_BV,  .mbox_reg = GEN6_VBSYNC },
  					[VECS_HW] = { .wait_mbox = MI_SEMAPHORE_SYNC_BVE, .mbox_reg = GEN6_VEBSYNC },
  				},
  				[VECS_HW] = {
  					[RCS_HW] =  { .wait_mbox = MI_SEMAPHORE_SYNC_VER, .mbox_reg = GEN6_RVESYNC },
  					[VCS_HW] =  { .wait_mbox = MI_SEMAPHORE_SYNC_VEV, .mbox_reg = GEN6_VVESYNC },
  					[BCS_HW] =  { .wait_mbox = MI_SEMAPHORE_SYNC_VEB, .mbox_reg = GEN6_BVESYNC },
  				},
  			};
  			u32 wait_mbox;
  			i915_reg_t mbox_reg;
  
  			if (i == engine->hw_id) {
  				wait_mbox = MI_SEMAPHORE_SYNC_INVALID;
  				mbox_reg = GEN6_NOSYNC;
  			} else {
  				wait_mbox = sem_data[engine->hw_id][i].wait_mbox;
  				mbox_reg = sem_data[engine->hw_id][i].mbox_reg;
  			}
  
  			engine->semaphore.mbox.wait[i] = wait_mbox;
  			engine->semaphore.mbox.signal[i] = mbox_reg;
  		}
  	}
  
  	return;
  
  err_obj:
  	i915_gem_object_put(obj);
  err:
  	DRM_DEBUG_DRIVER("Failed to allocate space for semaphores, disabling\n");
  	i915.semaphores = 0;
  }
  
  static void intel_ring_init_irq(struct drm_i915_private *dev_priv,
  				struct intel_engine_cs *engine)
  {
  	engine->irq_enable_mask = GT_RENDER_USER_INTERRUPT << engine->irq_shift;
  
  	if (INTEL_GEN(dev_priv) >= 8) {
  		engine->irq_enable = gen8_irq_enable;
  		engine->irq_disable = gen8_irq_disable;
  		engine->irq_seqno_barrier = gen6_seqno_barrier;
  	} else if (INTEL_GEN(dev_priv) >= 6) {
  		engine->irq_enable = gen6_irq_enable;
  		engine->irq_disable = gen6_irq_disable;
  		engine->irq_seqno_barrier = gen6_seqno_barrier;
  	} else if (INTEL_GEN(dev_priv) >= 5) {
  		engine->irq_enable = gen5_irq_enable;
  		engine->irq_disable = gen5_irq_disable;
  		engine->irq_seqno_barrier = gen5_seqno_barrier;
  	} else if (INTEL_GEN(dev_priv) >= 3) {
  		engine->irq_enable = i9xx_irq_enable;
  		engine->irq_disable = i9xx_irq_disable;
  	} else {
  		engine->irq_enable = i8xx_irq_enable;
  		engine->irq_disable = i8xx_irq_disable;
  	}
  }
  
  static void i9xx_set_default_submission(struct intel_engine_cs *engine)
  {
  	engine->submit_request = i9xx_submit_request;
  }
  
  static void gen6_bsd_set_default_submission(struct intel_engine_cs *engine)
  {
  	engine->submit_request = gen6_bsd_submit_request;
  }
  
  static void intel_ring_default_vfuncs(struct drm_i915_private *dev_priv,
  				      struct intel_engine_cs *engine)
  {
  	intel_ring_init_irq(dev_priv, engine);
  	intel_ring_init_semaphores(dev_priv, engine);
  
  	engine->init_hw = init_ring_common;
  	engine->reset_hw = reset_ring_common;
  
  	engine->context_pin = intel_ring_context_pin;
  	engine->context_unpin = intel_ring_context_unpin;
  
  	engine->request_alloc = ring_request_alloc;
  
  	engine->emit_breadcrumb = i9xx_emit_breadcrumb;
  	engine->emit_breadcrumb_sz = i9xx_emit_breadcrumb_sz;
  	if (i915.semaphores) {
  		int num_rings;
  
  		engine->emit_breadcrumb = gen6_sema_emit_breadcrumb;
  
  		num_rings = INTEL_INFO(dev_priv)->num_rings - 1;
  		if (INTEL_GEN(dev_priv) >= 8) {
  			engine->emit_breadcrumb_sz += num_rings * 6;
  		} else {
  			engine->emit_breadcrumb_sz += num_rings * 3;
  			if (num_rings & 1)
  				engine->emit_breadcrumb_sz++;
  		}
  	}
  
  	engine->set_default_submission = i9xx_set_default_submission;
  
  	if (INTEL_GEN(dev_priv) >= 8)
  		engine->emit_bb_start = gen8_emit_bb_start;
  	else if (INTEL_GEN(dev_priv) >= 6)
  		engine->emit_bb_start = gen6_emit_bb_start;
  	else if (INTEL_GEN(dev_priv) >= 4)
  		engine->emit_bb_start = i965_emit_bb_start;
  	else if (IS_I830(dev_priv) || IS_I845G(dev_priv))
  		engine->emit_bb_start = i830_emit_bb_start;
  	else
  		engine->emit_bb_start = i915_emit_bb_start;
  }
  
  int intel_init_render_ring_buffer(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  	int ret;
  
  	intel_ring_default_vfuncs(dev_priv, engine);
  
  	if (HAS_L3_DPF(dev_priv))
  		engine->irq_keep_mask = GT_RENDER_L3_PARITY_ERROR_INTERRUPT;
  
  	if (INTEL_GEN(dev_priv) >= 8) {
  		engine->init_context = intel_rcs_ctx_init;
  		engine->emit_breadcrumb = gen8_render_emit_breadcrumb;
  		engine->emit_breadcrumb_sz = gen8_render_emit_breadcrumb_sz;
  		engine->emit_flush = gen8_render_ring_flush;
  		if (i915.semaphores) {
  			int num_rings;
  
  			engine->semaphore.signal = gen8_rcs_signal;
  
  			num_rings = INTEL_INFO(dev_priv)->num_rings - 1;
  			engine->emit_breadcrumb_sz += num_rings * 8;
  		}
  	} else if (INTEL_GEN(dev_priv) >= 6) {
  		engine->init_context = intel_rcs_ctx_init;
  		engine->emit_flush = gen7_render_ring_flush;
  		if (IS_GEN6(dev_priv))
  			engine->emit_flush = gen6_render_ring_flush;
  	} else if (IS_GEN5(dev_priv)) {
  		engine->emit_flush = gen4_render_ring_flush;
  	} else {
  		if (INTEL_GEN(dev_priv) < 4)
  			engine->emit_flush = gen2_render_ring_flush;
  		else
  			engine->emit_flush = gen4_render_ring_flush;
  		engine->irq_enable_mask = I915_USER_INTERRUPT;
  	}
  
  	if (IS_HASWELL(dev_priv))
  		engine->emit_bb_start = hsw_emit_bb_start;
  
  	engine->init_hw = init_render_ring;
  	engine->cleanup = render_ring_cleanup;
  
  	ret = intel_init_ring_buffer(engine);
  	if (ret)
  		return ret;
  
  	if (INTEL_GEN(dev_priv) >= 6) {
  		ret = intel_engine_create_scratch(engine, PAGE_SIZE);
  		if (ret)
  			return ret;
  	} else if (HAS_BROKEN_CS_TLB(dev_priv)) {
  		ret = intel_engine_create_scratch(engine, I830_WA_SIZE);
  		if (ret)
  			return ret;
  	}
  
  	return 0;
  }
  
  int intel_init_bsd_ring_buffer(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	intel_ring_default_vfuncs(dev_priv, engine);
  
  	if (INTEL_GEN(dev_priv) >= 6) {
  		/* gen6 bsd needs a special wa for tail updates */
  		if (IS_GEN6(dev_priv))
  			engine->set_default_submission = gen6_bsd_set_default_submission;
  		engine->emit_flush = gen6_bsd_ring_flush;
  		if (INTEL_GEN(dev_priv) < 8)
  			engine->irq_enable_mask = GT_BSD_USER_INTERRUPT;
  	} else {
  		engine->mmio_base = BSD_RING_BASE;
  		engine->emit_flush = bsd_ring_flush;
  		if (IS_GEN5(dev_priv))
  			engine->irq_enable_mask = ILK_BSD_USER_INTERRUPT;
  		else
  			engine->irq_enable_mask = I915_BSD_USER_INTERRUPT;
  	}
  
  	return intel_init_ring_buffer(engine);
  }
  
  int intel_init_blt_ring_buffer(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	intel_ring_default_vfuncs(dev_priv, engine);
  
  	engine->emit_flush = gen6_ring_flush;
  	if (INTEL_GEN(dev_priv) < 8)
  		engine->irq_enable_mask = GT_BLT_USER_INTERRUPT;
  
  	return intel_init_ring_buffer(engine);
  }
  
  int intel_init_vebox_ring_buffer(struct intel_engine_cs *engine)
  {
  	struct drm_i915_private *dev_priv = engine->i915;
  
  	intel_ring_default_vfuncs(dev_priv, engine);
  
  	engine->emit_flush = gen6_ring_flush;
  
  	if (INTEL_GEN(dev_priv) < 8) {
  		engine->irq_enable_mask = PM_VEBOX_USER_INTERRUPT;
  		engine->irq_enable = hsw_vebox_irq_enable;
  		engine->irq_disable = hsw_vebox_irq_disable;
  	}
  
  	return intel_init_ring_buffer(engine);
  }
  